The growth of entire functions of exponential type and characteristics of distributions of points along a straight line

TL;DR

This paper establishes necessary and sufficient conditions for the arrangement of point distributions in the complex plane that allow for the existence of entire functions of exponential type with prescribed zero sets, extending classical results.

Contribution

It generalizes the classical theorem of Malliavin and Rubel by providing new criteria involving logarithmic characteristics and measures for point distributions on the complex plane.

Findings

Criteria based on logarithmic characteristics for point distributions.

Conditions involving asymptotic separation and Lindelöf-type conditions.

Extension of classical theorems to more general distributions.

Abstract

Let $Z$ and $W$ be a pair of point distributions of finite upper density on the complex plane $\mathbb C$ with the real axis $\mathbb R$. We give several variants of necessary and at the same time sufficient conditions for their arrangement, under which for every entire function of exponential type $g\neq 0$ vanishing on $W$, there is, respectively, either an entire function of exponential type $f\neq 0$ vanishing on $Z$ and satisfies one of the two variants of the constraints: 1) $|f(iy)|\leq |g(iy)|$ at each $y\in \mathbb R$, i.e. everywhere on the imaginary axis $i\mathbb R$, 2) $\ln |f(iy)|\leq \ln |g(iy)|+o(|y|)$ as $y\to \pm \infty$, or for any number $\varepsilon >0$ there is an entire function of exponential type $f\neq 0$ vanishing on $Z$ and satisfies the inequality $\ln \bigl|f(iy)\bigr|\leq \ln \bigl|g(iy)\bigr|+\varepsilon |y|$ for all $y\in \mathbb R\setminus E$, where $E\subset \mathbb R$ is a set of finite linear Lebesgue measure. Our study is carried out within the framework of generalization of the development of the classical theorem of P. Malliavin and L.A. Rubel of the 1960s, where the case of the location of $Z\subset \mathbb R^+$ and $W\subset \mathbb R^+$ on the positive semiaxis $\mathbb R^+\subset \mathbb R$ is considered. Our criteria are given in terms of special logarithmic characteristics and (sub)measures for $Z$ and $W$. At the same time, in the third variant, there are no additional requirements for $Z$ and $W$, but in the first and second variants, we require the asymptotic separation of $Z$ and $W$ by angles from the imaginary axis together with the Lindel\"of-type condition for $W$ along the imaginary axis $iR$ on a certain symmetry of the imaginary parts of $1/w$ for $w\in W$ in the form $\Bigl|\sum_{1\leq |w|\leq r}\Im (1/w)\Bigr|=O(1)$ as $r\to +\infty$.